For the mostpart the following definitions are nearly identical, yet have distinct definitions to maintain the accuracy of their meanings. Please also see our research references for additional information.

Since the "atheism" classification is not justified by claims for or against theistic or anti-theistic positions, the burden of proof is not applicable. Although it's certainly possible to have reasons for choosing atheism, such justification is entirely optional.

Further clarification

For the sake of completeness, and due to the wide-spectrum of theistic deity-dependent concepts (including supernatural agents - such as angels and demons - which don't qualify as goddesses or gods), "atheism" may also therefore be classified implicitly as the "absence of belief in deities and [theistic deity-dependent] supernatural agents."

Since the "atheism" classification is not justified by claims for or against theistic or anti-theistic positions, the burden of proof does not apply to atheists. Although it's certainly possible to have reasons for choosing to be an atheist, such justification is entirely optional.

Further clarification

For the sake of completeness, and due to the wide-spectrum of theistic deity-dependent concepts (including supernatural agents - such as angels and demons - which don't qualify as goddesses or gods), an "atheist" may also therefore be classified implicitly as the "absent of belief in deities and [theistic deity-dependent] supernatural agents."